Yes, you’re absolutely noticing something real—and it's a known quirk (or frustration) in Meta's attribution model.
Facebook (Meta) can and often does take credit for conversions that were actually driven by other channels, including email campaigns, if someone clicked or even viewed a Facebook ad within the attribution window.
Here’s how it works:
So if you:
Run a Facebook retargeting ad
Send a sales email to the same user the next day
They click the email and purchase...
Meta still might show it as a conversion in your ads dashboard.
Why does this happen?
Overlapping audiences: Your email list and retargeting audience are often the same people.
Attribution windows: Meta is “watching” for any conversions that happen within that window after a user saw or clicked an ad.
What you can do:
Use UTM tracking in your emails and analyze results in Google Analytics to separate true email conversions.
Compare Meta’s numbers to first-click or last-click data in GA to get a better picture.
Consider adjusting the attribution setting in Meta Ads Manager (e.g., change from 7-day click/1-day view to 1-day click) if over-reporting becomes a serious issue.
So yes—Meta can inflate ROAS during an email campaign. It’s not “stealing” conversions maliciously, but the attribution model gives it more credit than it may deserve. Always good to double-check against GA or your backend analytics.